1. Field of the Invention
The present invention relates to an air cleaner unit for a vehicle. More particularly, the present invention relates to an air cleaner which is particularly useful for an all terrain vehicle.
2. Description of Background Art
A conventional air cleaner for a vehicle is disclosed in Japanese Unexamined Patent Publication No. H4-255560. This air cleaner is provided with an air cleaner box mounted on a vehicle body, an air cleaner element mounted forward of the lower portion in the air cleaner box, an exhaust duct mounted forward of the lower portion of the air cleaner box and for supplying air cleaned by the air cleaner element, and an intake duct for introducing air into the air cleaner box.
The intake duct is horizontally inserted into the air cleaner box through the front upper portion of the air cleaner box. A downstream end portion of the intake duct is bent along the rear wall of the air cleaner box and a downstream opening of the intake duct faces toward the bottom portion of the air cleaner box in the back of the air cleaner.
The air introduced through the intake duct is introduced into the air cleaner box and is made to change flow through a passage along a rear wall of the air cleaner box. The air is then directed to the bottom of the air cleaner in the back of the air cleaner element.
This kind of conventional air cleaner is constituted such that the air introduced through the intake duct is introduced to the bottom portion of the air cleaner box. This avoids the air cleaner element from being directly struck by the air entering the air cleaner box.
The flow of the air introduced in the above manner prevents moisture and dust mixed in the introduced air from contacting the air cleaner element. This is advantageous, since the air cleaner is prevented from being clogged.
However, even the above-mentioned conventional air cleaner unit is problematic. Specifically, in the conventional air cleaner described above, the intake duct is horizontally inserted into the air cleaner box through the front upper portion of the air cleaner box and a downstream end portion of the intake duct is bent along the rear wall of the air cleaner box to oppose a rear end opening of the intake duct to the bottom portion of the air cleaner box in the back of the air cleaner. In view of this construction, the path of the intake duct is sharply bent in the narrow region of the air cleaner box. As a result, this presents a problem in that the path of the intake duct is elongated. Furthermore, flow resistance is increased by the bent portion to thereby decrease the intake efficiency of the air cleaner unit.
For example, in general, an all terrain vehicle is provided with a fuel tank in front of the air cleaner box described above. Furthermore, in a vehicle constructed in this manner, the intake duct is sometimes required to be further bent to avoid interference with the fuel tank. This results in further exacerbating the above-mentioned problem.
In view of the conventional problems described above, the present invention has been made and an object of the present invention is to provide an air cleaner unit capable of preventing the introduced air from directly striking the air cleaner element and capable of reducing a decrease in intake efficiency to a minimum.
In order to accomplish the above-mentioned object, an air cleaner unit for a vehicle, according to a first aspect of the present invention includes: an air cleaner box mounted on a vehicle body; an air cleaner element mounted on the upper portion in the air cleaner box; an exhaust port formed at the upper front portion of the air cleaner box and communicating with the exhaust portion of the air cleaner element; an intake port formed on the side of the exhaust port at the front portion of the air cleaner box; and an intake duct inserted into the air cleaner box through the intake port, wherein the downstream of the intake duct is mounted linearly toward the lower rear portion in the air cleaner box and wherein the opening of the downstream of the intake duct is below the air cleaner element.
An air cleaner unit for a vehicle according to a second aspect of the present invention includes a fuel tank mounted in front of the air cleaner box and a depression on a side thereof along the back and forth direction of the vehicle, wherein the intake duct is extended from the front portion of the air cleaner box to the upper and slanting direction and then along the depression on the fuel tank, whereby the opening of the upstream of the intake duct faces in a forward direction of the vehicle.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.